Berlin 2015 – scientific programme
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 33: P5: Microswimmers, Active Liquids
CPP 33.1: Poster
Tuesday, March 17, 2015, 14:00–16:00, Poster C
Light-driven Microswimmers: Run-and-Tumble depend on the conditions — •Celia Lozano1,2, Jannick Fischer1, Felix Kümmel1, and Clemens Bechinger1,2 — 12. Physikalisches Institut, Universität Stuttgart — 2Max-Planck-Institut für Intelligente Systeme, Stuttgart
Recently, notable improvements regarding the understanding of the dynamics of active particles have been obtained [1]. While their swimming motion under bulk conditions is rather well understood, only little is known about the dynamical properties of active particles under conditions where the Peclet (Pe) number various as a function of the particle position. We present an experimental study, where active motion is achieved by diffusiophoretic forces in a binary solvent and where the Pe number is controlled by the light intensity [2]. In the presence of one-dimensional periodic intensity patterns, we observe the accumulation/depletion of active particles in regions with low/high illumination, i.e. with small/large Pe numbers. We study the steady state particle density variations as a function of the ratio of the persistence length of active particles and the strip width of the intensity pattern and compare our results to numerical simulations. We expect, that our findings contribute to the understanding of pattern formation of chemotactic organisms in chemical gradients.
[1] B. ten Hagen, F. Kümmel, R. Wittkowski, D. Takagi, H. Löwen, and C. Bechinger Nature Comm. 5, 4829 (2014) [2] I. Buttinoni, G. Volpe, F. Kümmel, G. Volpe, and C. Bechinger J. Phys.: Cond. Mat. 24, 284129 (2012)